JPS6037599B2 - induction heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention utilizes electromagnetic induction while continuously conveying a plurality of the largest billets to be heated through an induction coil using a carry-in device and a carry-out device comprising, for example, pinch rollers. This invention relates to an induction heating device that heats this long billet by its action.

In general, in this type of induction heating apparatus, if the length of the billet to be heated is short, the heating temperature unevenness in the longitudinal direction is not much of a problem, but if the billet is long (approximately 50
Since the processing speed (conveying speed) of the front and rear billets of 0 to 1000 m/ is extremely slow, a considerable amount of time will elapse from when the leading end of the billet exits the induction coil until the trailing end exits.

Therefore, even if a long billet is heated on average as a whole by the induction coil, the leading end, which exits from the induction coil first and begins to cool down, is necessarily the same as the rear end, which exits later. This will result in a temperature difference of . Therefore, the elongated billet that has been subjected to the induction heating process using the induction coil has considerable temperature unevenness in the longitudinal direction, which of course has an adverse effect on the next forging process. The present invention has been made with this point in mind, and it is an object of the present invention to provide an induction heating device in which the temperature unevenness in the longitudinal direction of the long billet described above is reduced as much as possible.

That is, FIG. 1 shows an embodiment of this invention,
1 is a plurality of billets to be heated; 2 is an induction coil having a coil length sufficient to uniformly heat each billet; A is an induction coil 2 that continuously moves a plurality of billets to be heated at a predetermined speed in the longitudinal direction; This carrying device A includes a pair of pinch rollers 3, 3 that press against the billet 1 from both sides, and a variable speed reduction motor that drives the pinch rollers 3, 3 in a predetermined direction at a predetermined speed. The driving device 4 is composed of a drive device 4 and the like.

Reference numeral B denotes an unloading device that pulls out the billet 1 sent out from the induction coil 2. This unloading device B includes a pair of pinch rollers 5, 5 that press against the billet 1 from both sides, and a pair of pinch rollers 5, 5 that move the pinch rollers 5, 5 in a predetermined direction. The drive unit 6 includes a speed changeable deceleration motor or the like that drives at a predetermined speed. The reason why the drive device 6 is variable speed is as follows.
This is to allow the unloading speed to be set optimally depending on the billet size, processing speed, etc. Reference numeral 7 denotes a detection element made of a conductor, one end of which is rotatably supported.

A rotary solenoid 8 is normally energized and holds the detection element 7 at a fixed position.

11 is a relay, and when the tip of the billet 1 comes out from the induction coil 2 and contacts the detection element 7 as shown, the power supply 12 is connected.
An open circuit of - relay 11 - detection element 7 - billet 1 - power supply 12 is formed and operated, deenergizing the rotary solenoid 8.

When the rotary solenoid 8 is deenergized, the detection element 7 rotates counterclockwise to avoid engagement with the billet 1. 9 is a controller, the tip of billet 1 is induction coil 2
When the detection element 7 detects that the carrier has come out of the carrier, a signal is sent to the carrying-in device A to switch to high-speed operation.

In addition, the above-mentioned detection element 7, rotary solenoid 8, controller 9
The control device C is configured by: Since the induction heating device of the present invention is configured as described above, the tip of the billet 1, which is heated by induction while passing through the induction coil 2 by the loading device A, reaches the outlet of the transfer coil 2 and waits. When the detecting element 7 collides with this, the controller 9 first sends a signal to the loading device A to switch to high-speed operation, and at the same time, the rotary solenoid 8 is deenergized by operating the relay 11. , the detection element 7 is avoided in a direction in which it does not engage the billet toe.

By the above-described operation, the pinch rollers 3,
As shown in Figure 2, the conveyance speed of No. 3 varies from "V," to "
V2'', the billet 1 that started coming out of the induction coil 2 is rapidly fed out and is bitten by the pinch rollers 5, 5 of the conveying device B whose conveying speed is ``V2'', and is then transferred to the next stage, for example, forging. Transported to the process unit. The time during which the pinch rollers 3, 3 are driven at the conveying speed V2 is approximately equal to the time from the time when the tip of the billet comes into contact with the detection element 1 until the tip of the billet is bitten by the pinch rollers 5, 5. The drive device 4 can be controlled, for example, by a timer or the like, so that

Normally, the distance between the outlet of the induction coil 2 and the pinch rollers 5, 5 is set shorter than the length of one billet 1, so that when the tip of the billet 1 is bitten by the pinch rollers 5, 5. When the conveyance speed of the pinch rollers 3, 3 is returned from V2 to V by a timer or the like, the pinch roller 5
, 5, the billets other than the most advanced one, which are rapidly pulled out at the conveyance speed V2, remain in the induction coil 2 and are conveyed again at the conveyance speed V, until they reach the exit of the induction coil 2. . Further, the rotary solenoid 8 is configured to be re-energized immediately after the most advanced billet 1 is conveyed out by the pinch rollers 5 at a conveyance speed V2, so as to return the detection element 7 to the illustrated position. According to this invention, as described above, when the tip of the billet 1 comes out from the induction coil 2, this is detected and the billet 1 is rapidly pulled out from the induction coil 2. The temperature unevenness up to the rear end portion is approximately averaged from the state shown in FIG. 3 to the state shown in FIG. 4. Therefore, according to the present invention, the temperature unevenness in the longitudinal direction of the billet can be minimized with an extremely simple configuration, which has an excellent effect that does not adversely affect the next processing step. . In the above-described embodiment, a rotary solenoid was used as the device for operating the detection element 7 of the control device C, but an oil or air cylinder may also be used.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, FIG. 2 is a waveform diagram showing the conveying speed of the pinch roller 3 of the carrying device A, and FIGS. FIG. 2 is a temperature distribution diagram in the longitudinal direction of the pellet. In the drawings, 1 is a billet, 2 is a transfer coil, A is a loading device, B is a loading device, C is a control device, 3 and 5 are pinch rollers, 4 and 6 are driving devices, 7 is a detection element, and 8 is a rotary Solenoid 9 is a controller. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. An induction coil having a coil length longer than the length of one billet to be heated and for induction heating a billet to be heated carried into the interior, and a plurality of heating coils within this induction coil. A loading device that continuously carries in the billets to be loaded; and detecting when the tip of the billet comes out from the induction coil, increasing the feed speed of the loading device for a predetermined time, and returning to the original feed after the predetermined time has elapsed. a control device for returning the billet to the same speed, and an unloading device for unloading the cutting edge billet that has been accelerated by the loading device and has come out of the induction coil at a speed equal to or higher than the increased feeding speed. An induction heating device characterized by: 2. Claim 1, characterized in that the carry-in device and the carry-out device are constituted by a plurality of pinch rollers that press against the billet from both sides, and a drive device that drives each pinch roller in a predetermined direction at a predetermined speed. The induction heating device described. 3. A control device that collides with the billet coming out of the induction coil and avoids the billet with a detection element, a rotary solenoid that avoids the billet in a direction where the detection element does not engage the billet, and a rotary solenoid that avoids the billet when the tip of the billet comes out of the induction coil. 2. The induction heating device according to claim 1, further comprising a controller that sends a signal to switch the device to high-speed operation. 4. The induction heating device according to claim 1 or 2, characterized in that a variable speed reduction motor is used as a drive device for the carry-in device and the carry-out device.